1. Field of the Invention
This invention relates to machines for forming round bales of crop material and has particular reference to the wrapping of bales formed in such machines with a flexible binding material such as conventional bale twine.
2. Description of the Prior Art
It was customary for a great number of years to harvest and store forage crops by mowing the crop in the field, permitting it to dry to a reasonable extent, forming it into windrows, and then compacting the windrows into rectangular bales by conventional hay baling machines. To store rectangular bales, they must either be conveyed to a shed or barn and stacked or, if they are left in a field, they must be covered with waterproof material to prevent rotting.
In recent years, an innovation has occurred in the baling art in the form of a machine which handles the cut crop material in a manner to coil the same into a relatively compact roll, usually of very substantial size and weighing many hundreds of pounds, for example between 1000 and 1500 pounds (455 and 680 kilograms). One of the principal advantages of roll type bales of forage crops is that they may be much more readily stored, as well as fed to herbivorous animals, simply by letting the rolls lie in the field of use or in a feed lot. In this way, animals may readily feed upon such rolls at will and the rolls are self water-shedding and so do not rot.
Several methods of forming of compact rolls of crop material have been devised and one of these involves rolling the swath or windrow of material along the ground until a roll of desired size is obtained. Another, and more successful, method is disclosed in U.S. Pat. No. 3,815,345 in which a swath or windrow of material is picked up from the field and directed onto a supporting conveyor. This conveyor transports the material in one direction whilst an upper apron, usually positioned above the supporting conveyor, moves in the opposite direction, thereby imparting to the crop material, which it contacts, a circular motion. In an off-the-ground roll forming machine of this type it has been found that to provide optimum weathering characteristics the bale must be rolled and maintained as tightly as possible, consistent with the animals being able to feed off it. The crop material is compacted during the bale forming operation by various types of compression devices which apply pressure to the periphery of the bale as it is being formed. To maintain this compactness, the bale must be secured as tightly as possible when it has been formed to the required size. To this end, the formed bale is wrapped within the machine with a suitable wrapping material such as twine or wire, for example.
For the purpose of illustrating a typical type of apparatus for disposing a roving type strand of wrapping material in a spiral manner around a round bale, attention is directed to U.S. Pat. No. 3,910,178. In the machine disclosed in this specification, the application of the binding material to the formed roll is at least in part effected manually by an operator sitting, for example, upon the seat of the tractor which propels the machine along a field.
Reference is also made to U.S. Pat. No. 3,913,473 in which the roving of the wrapping material is effected by a hydraulically-actuated mechanism which moves a twine directing arm substantially in a horizontal plane whilst distributing the wrapping material from the outer end of the arm which moves in an arcuate path between opposite sides of the bale forming machine.
A problem with known roll forming machines often arises at the commencement of a wrapping cycle during which a formed roll is bound with wrapping material. When the twine dispensing mechanism is in its rest position, a predetermined length of twine or other wrapping material dangles from the outlet end thereof. To start the wrapping of a formed roll, the operator swings the dispensing mechanism into the vicinity of the roll forming region, whereby the length of twine mentioned above contacts the bottom apron or conveyor of the roll forming chamber and the layer of crop material being fed to this chamber. It is the intention that the free end of twine be caught up by the crop material about to be added to the roll so as effectively to attach the free end of the twine to the roll so that actual wrapping can start.
Usually there is also provided some kind of tensioning device whereby a predetermined tension is applied to the twine or other wrapping material as it is wrapped around the crop roll so that the twine is tightly wrapped therearound to provide a crop roll of good stability. This tensioning may cause hesitation in the take up of the free end of the twine by the roll and thus the start of the wrapping cycle may be delayed. Occasionally, the wrapping cycle never commences. k
It is the object of the present invention to avoid or to attenuate this problem.
According to the present invention there is provided a crop material roll forming machine having a frame, means on the frame defining a roll forming region, a dispensing mechanism mounted on the frame and movable from a rest position across the roll forming region to dispense material for wrapping a bale in use formed in the machine, tensioning means associated with the dispensing mechanism and operable to tension the wrapping material as it is being applied to a crop roll, and means engageable with the tensioning means to render the latter inoperative at a predetermined point in the dispensing movement of the dispensing mechanism.
Preferably, the dispensing mechanism comprises an elongate wrapping material directing arm of U-shaped cross-section and adapted to receive wrapping material between the limbs thereof. The directing arm may have an inlet for the wrapping material facing away from the roll forming region and an outlet for the wrapping material facing towards the roll forming region and movable back and forth across the machine in the vicinity thereof. The tensioning means may be pivotably mounted on the directing arm intermediate its ends and may comprise a tensioning member extending between the limbs of the U-shaped arm close to the bottom thereof. The tensioning member may comprise a leg which, in the operative position, is positioned parallel to and closely adjacent the bottom of the U-shaped directing arm so that wrapping material is engaged therebetween. Preferably, the tensioning leg is pivotable away from the bottom of the U-shaped directing arm in a direction generally corresponding to the intended direction of the passage of the wrapping material through the directing arm. This movement may be opposed by spring means extending between the tensioning means and the directing arm. The means engageable with the tensioning means may comprise a cam operable, when engaged by the tensioning means, to pivot the tensioning leg in said direction opposite to that caused by the action of the spring means. The cam may be secured to a fixed rod extending between opposed sides of the machine and is so positioned relative to the path of the dispensing means that the tensioning means are rendered inoperative, at the moment the dispensing mechanism has its outlet end closest to the roll forming region.